diff --git a/runtime/onert/api/nnfw/src/nnfw_session.cc b/runtime/onert/api/nnfw/src/nnfw_session.cc
index eaeb2999718..7a559d8a2ca 100644
--- a/runtime/onert/api/nnfw/src/nnfw_session.cc
+++ b/runtime/onert/api/nnfw/src/nnfw_session.cc
@@ -113,6 +113,13 @@ std::string trim(std::string_view value)
   return std::string(value.substr(begin, end - begin + 1));
 }
 
+std::string inferModelType(const std::string &filename)
+{
+  std::filesystem::path file_path(filename);
+  std::string ext = file_path.extension().string();
+  return ext.empty() ? "" : ext.substr(1);
+}
+
 bool loadConfigure(const std::string cfgfile, onert::util::CfgKeyValues &keyValues)
 {
   std::ifstream ifs(cfgfile);
@@ -377,7 +384,21 @@ NNFW_STATUS nnfw_session::load_model_from_path(const char *path)
     for (uint16_t i = 0; i < num_models; ++i)
     {
       const auto model_file_path = package_dir / models[i].asString();
-      const auto model_type = model_types[i].asString();
+      std::string model_type;
+
+      // Use model-types if available and not empty, otherwise infer from file extension
+      if (!model_types.empty() && i < model_types.size())
+        model_type = model_types[i].asString();
+      else
+        model_type = inferModelType(models[i].asString());
+      if (model_type.empty())
+      {
+        std::cerr << "Error: Cannot determine model type for '" << models[i].asString() << "'."
+                  << "Please specify model-types in MANIFEST or use a file with valid extension."
+                  << std::endl;
+        return NNFW_STATUS_ERROR;
+      }
+
       auto model = loadModel(model_file_path.string(), model_type);
       if (model == nullptr)
         return NNFW_STATUS_ERROR;